title: Is there a cerebellar compensatory effort in first-episode, treatment-naive major depressive disorder at rest?
abstract: BACKGROUND
  This study was undertaken to explore whether there is a cerebellar compensatory response in patients with first-episode, treatment-naive major depressive disorder (MDD). The cerebellar compensatory response is defined as a cerebellar hyperactivity which would be inversely correlated with both the activation of the functionally connected cerebral regions and the depression severity.
  
  
  METHODS
  Resting-state functional magnetic resonance imaging (fMRI) data of 24 patients with MDD and 24 healthy subjects were analyzed with the fractional amplitude of low-frequency fluctuations (fALFF) and functional connectivity (FC) methods. The structural images were processed with the voxel-based morphometry (VBM) method.
  
  
  RESULTS
  Compared to healthy controls, depressed patients had significantly increased fALFF in the left Crus I and the left cerebellar lobule VI. FC analysis of these two seeded regions found that depressed patients had increased FC between the left Crus I and the right hippocampus, but had decreased FC between the left Crus I and the left inferior parietal lobule (IPL), and between the left cerebellar lobule VI and bilateral inferior temporal gyrus. No correlation was observed between the abnormal fALFF of the seeds and their connected regions and the depression severity or the executive function. The VBM results did not show significant reduction in gray or white matter volume in any above-mentioned region.
  
  
  CONCLUSIONS
  Our findings suggest that increased cerebellar activity at resting state may be a disease state phenomenon but not a compensatory response to the dysfunction of the default mode network (DMN) in MDD.
authors.affiliation: Mental Health Center, the First Affiliated Hospital, Guangxi Medical University; Nanning, Guangxi 530021, China. Electronic address: guowenbin76@163.com.
authors.forename: Wenbin
authors.initials: W
authors.lastname: Guo
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.forename: Jianrong
authors.initials: J
authors.lastname: Liu
authors.forename: Liuyu
authors.initials: L
authors.lastname: Yu
authors.forename: Zhikun
authors.initials: Z
authors.lastname: Zhang
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.forename: Huafu
authors.initials: H
authors.lastname: Chen
authors.forename: Changqing
authors.initials: C
authors.lastname: Xiao
mesh_terms: D000293:Adolescent; D000328:Adult; D002531:Cerebellum / Q000378:metabolism* / Q000473:pathology; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000378:metabolism*; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D012146:Rest / Q000502:physiology*; D055815:Young Adult
keywords: AAL; Anatomical Automatic Labeling; BOLD; CSF; Cerebellum; DMN; DPARSF; Data Processing Assistant for Resting-State fMRI; Default mode network; EPI; FC; FD; FOV; FWHM; Fractional amplitude of low-frequency fluctuations; Functional connectivity; GM; GRF; GSReg; Gaussian Random Field; HRSD; Hamilton Rating Scale for Depression; IPL; MDD; MPFC; MPRAGE; Major depressive disorder; PCC/PCu; ROI; TI; TR/TE; VBM; VMHC; WCST; WM; Wisconsin Card Sorting Test; blood oxygen level-dependent; cerebrospinal fluid; default mode network; echo-planar imaging; fALFF; fMRI; field of view; fractional amplitude of low-frequency fluctuations; framewise displacement; full width at half maximum; functional connectivity; functional magnetic resonance imaging; global signal regression; gray matter; inferior parietal lobule; inversion time; magnetization-prepared rapid gradient echo; major depressive disorder; medial prefrontal cortex; posterior cingulate cortex/precuneus; region of interest; repetition time/echo time; voxel-based morphometry; voxel-mirrored homotopic connectivity; white matter